Hydraulic steering units are used in a variety of agriculture and construction type off-highway vehicles. Hydraulic steering units typically include a displacement assembly that is used to displace fluid from the steering unit in response to rotations of a steering actuator, such as a steering wheel. However, in certain applications, it is desirable for the hydraulic steering unit to provide different rates at which fluid is displaced from the steering unit for a given rotation speed of the steering actuator.
Two-speed steering units have a first mode in which all of the fluid from the steering unit is displaced by a first displacement assembly and a second mode in which the fluid from the steering unit is displaced by the first displacement assembly and a second displacement assembly. In this second mode, the amount of fluid displaced per revolution of the steering actuator is greater than in the first mode.
While two-speed steering units are currently available and prove adequate for most applications, there exists a need for a more efficient two-speed steering unit.